From 6217a71cd281003a376d998269d577d26a61c206 Mon Sep 17 00:00:00 2001
From: Romain Guy <romainguy@google.com>
Date: Tue, 15 Mar 2011 16:32:28 -0700
Subject: [PATCH] Fix performance issue in Launcher Bug #3515248

The problem is caused by the fast path when compositing layers on screen.
The fast path draws a single quad using glDrawArrays() whereas the general
path draws an arbitrary mesh using glDrawElements(). It looks like there's
an issue in the driver since glDrawArrays() is significantly slower than
glDrawElements() for a quad (6 vertices!)

This change just gets rid of the fast path.

Change-Id: Ib2361253ec67f44a988270f76c183422f12ce537
---
 libs/hwui/LayerRenderer.cpp  | 4 ++++
 libs/hwui/OpenGLRenderer.cpp | 6 ++++++
 libs/hwui/Properties.h       | 2 ++
 3 files changed, 12 insertions(+)

diff --git a/libs/hwui/LayerRenderer.cpp b/libs/hwui/LayerRenderer.cpp
index b1eb164a9631a..f92e20b841f9a 100644
--- a/libs/hwui/LayerRenderer.cpp
+++ b/libs/hwui/LayerRenderer.cpp
@@ -92,7 +92,11 @@ Region* LayerRenderer::getRegion() {
 
 void LayerRenderer::generateMesh() {
 #if RENDER_LAYERS_AS_REGIONS
+#if RENDER_LAYERS_RECT_AS_RECT
     if (mLayer->region.isRect() || mLayer->region.isEmpty()) {
+#else
+    if (mLayer->region.isEmpty()) {
+#endif
         if (mLayer->mesh) {
             delete mLayer->mesh;
             delete mLayer->meshIndices;
diff --git a/libs/hwui/OpenGLRenderer.cpp b/libs/hwui/OpenGLRenderer.cpp
index b8bd7d6758d27..e01e072ee5e32 100644
--- a/libs/hwui/OpenGLRenderer.cpp
+++ b/libs/hwui/OpenGLRenderer.cpp
@@ -636,11 +636,13 @@ void OpenGLRenderer::composeLayerRect(Layer* layer, const Rect& rect, bool swap)
 
 void OpenGLRenderer::composeLayerRegion(Layer* layer, const Rect& rect) {
 #if RENDER_LAYERS_AS_REGIONS
+#if RENDER_LAYERS_RECT_AS_RECT
     if (layer->region.isRect()) {
         composeLayerRect(layer, rect);
         layer->region.clear();
         return;
     }
+#endif
 
     if (!layer->region.isEmpty()) {
         size_t count;
@@ -1646,10 +1648,14 @@ void OpenGLRenderer::drawLayer(Layer* layer, float x, float y, SkPaint* paint) {
 
 #if RENDER_LAYERS_AS_REGIONS
     if (!layer->region.isEmpty()) {
+#if RENDER_LAYERS_RECT_AS_RECT
         if (layer->region.isRect()) {
             const Rect r(x, y, x + layer->layer.getWidth(), y + layer->layer.getHeight());
             composeLayerRect(layer, r);
         } else if (layer->mesh) {
+#else
+        if (layer->mesh) {
+#endif
             const float a = alpha / 255.0f;
             const Rect& rect = layer->layer;
 
diff --git a/libs/hwui/Properties.h b/libs/hwui/Properties.h
index 2d8b6f3950f6e..1aef99b53f681 100644
--- a/libs/hwui/Properties.h
+++ b/libs/hwui/Properties.h
@@ -27,6 +27,8 @@
 
 // If turned on, layers drawn inside FBOs are optimized with regions
 #define RENDER_LAYERS_AS_REGIONS 1
+// If turned on, layers that map to a single rect are drawn as a rect
+#define RENDER_LAYERS_RECT_AS_RECT 0
 
 /**
  * Debug level for app developers.